What would you recommend?

Just to add the City 'n Move says suitable from 6 months but its got a lie flat seat and UK safety regs would say this was ok from birth. But EU safety regs say otherwise. Its been classified as 6 months as the EU regs kick in soon I believe.

I'm needing to buy a pushchair- the sling is killing me which is a pain as we live in a first floor apartment with no hallway. LO doesn't nap so I send hours walking but I'm button my limit with the sling. I avoided getting a pram as I doubted I'd be able to get it up and down easily or store it but I'm going to have to. We also have crap access via a narrow shale path so I really need this thing to be easy!

So specifics are: has to fold small as possible and easily as i have nowhere to put down LO, be suitable for 3 month old, be suitable for tall parents and not cost me the earth as I don't have time to save.